Today the UNAM community at large mourns the passing of Federico Sánchez Rodríguez. He got his bachelor’s degree from the School of Chemistry - UNAM, masters and PhD degrees from Biomedicas - UNAM, postdoc from UCSF, was a member of CIFN-UNAM now called CCG-UNAM (it’s his affiliation in this 1983 paper), and worked most of his career at IBT-UNAM.